Telephone-exchange system.



F. R. MGBBR'I'Y. vTELlizPHom: EXCHANGE SYSTEM. APPLmATx'oN FILED MAR. 1, 1911. 1,125,579. Patented Jau. 19, 1915.

l0 SHEETS-SHEILTLL F. R. MGBBRTY.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED MAR. I, 1911.

1,125,579. Patented Jan. 19, 1915,

10 SHEETS-SHEET 2.

Mw M- Fran/r M5 5er/y.

- F. R. MGBERTY.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED 1111111 1911.

MS Nv F. R. MGBERTY.

TELEPHONE EXCHANGE SYSTEM APPLICATION FILED MAR.1, 1911.

1,125,579, Patented .111119, 1915.

.10 SHBETSSHBET 4.

P. R. MGBERTY.

TELEPHONE EXCHANGE SYSTEM.

APPLICA IIIIIIIIIII AR. 1 1 s 1 1.

1,125,579, Patented Ja11.19, 1915.

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@OMA/6A P. R. MGBBRTY.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION IILED MAR.1,1911,

Patented Jau. 19, 1915.

10 SHEETSSHEBT 6.

F. R. MGBERTY.

TELEPHONE EXCHANGE SYSTEM.

APPpwATloN FILED MAR.1,1911.

LlQo

Patented Jan. 19, 1915.

10 SHEETS-SHEET 7.

F. R. MGBERTY. TELEPHONE EXCHANGE SYSTEM.

APPLICATION IILED MAR.1.1911. l

Patented Jan. 19, 1915A l/l//Y/Msses: //7 Ven/0r:

WW2 @M23/' Fran/r M5 .5er/y.

11. 11. MGBERTY. TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED MAR.1,1

Patented Jan. 19, 1915.

1() SHEETS-SHEET 9.

MNIM

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Wum

Fran/rf?. M'g 5er/y by F. R. MGBBRTY. TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED MAR.1, 1911.

1,125,579. Patented Jan.19,1915.

10 SHEETS-SHEET 10.

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incassa,

Specification of Letters Patent.

Patenten-ran. 1e, isis.

application med nenn 1, 1911. serial No. 611,630.

MCBERTY,

new and useful Improvement in Telephone- Exchange Systems, of which the following is in full, clear, Concise, and exact description.

My. invention relates to telephone exchange systems and contemplates in general an improved organization and arrangement of circuits and apparatus whereby the interconnection of telephone lines and trunk lines may be controlled and accomplished speedily and with precision.

The 'object of my invention is to provide an improved and novel telephone exchange system wherein the interconnection of telephone lines and trunk lines is accomplished by' means ofmechanical switching apparatus, such switching apparatus acting under the controlof a sender or selection controlling organism to accomplish the accurate and expeditious establishment of a desired connection.

A further objectv of my invention isY to provide in an exchan e in which the interconnection of subscri ers lines is accomplished by mechanical switching apparatus under the control of an operator improved and. novel means whereb the automatic line selection may be simply and easily controlled and whereby such controlling means may be automatically associated and dissociated with the mechanical switching apparatus at the proper stages in the operation of the system. My invention. therefore contemplates a telephone exchange system in which the interconnection of telephone lines and trunk lines is accomplished through mechanical switching apparatus comprising improved arrangements of circuits and apparatus whereby. allv the necessary functions of a modern telephone exchange system may be performed. 'in the most accurate, rapid and satisfactory manner. 'llhe specitic showing of my invention herein involved discloses whatgis lmown as a semi-mechanical telephone exchange system in which the interconnection of lines and trunk lines is accomplished by mechanical switching apparatus under the control of an operator, but such` system involves many improvements States, residing at New `which are 1ny no wayspecific to semimechanical` systems. It will therefore be understood that my invention is in no way confined tothe specific system and arrangement shown herein except asV limited by the hereinafter"r appended claims.

The, accompanying drawings which illustrate the preferred form of my invention show,.` moreover, various features which form no part of my presentinvention and are not claimed in this application. These features are claimed in my applications for Letters Patent as follows: Serial No. 573,516, filed July 23,1910, lfor Vautomatic vtelephone exchange selectors'4 (Case 191); Serial No. 516,769, 1ed` September l8, 1909,l for trunking system for telephone exchanges (Case 192) Serial No. 515,933, tiled September 2, 190.9, for selective ,controlling afnatus (Ca-se' 193) Serial No. 528,293, iiledpil'ovember 16, 1909., for telephone exchange systems (Case 194) Serial No. 531,369, filed December 4, 1909, for-tele hone exchange systems (Case 195) Serial lilo'. 533,928, filed December 18, 1909, for busy test Asysternfor party telephone lines (Case 196) Serial No. 573,- 517, led July 23,' 1910, for tele hone exchange .systems (Case 197) Sierial No; 57 l1,0189, filed July 27 1910, for telephone exchange systems (Case 198) Serial No. 588,840,1iled `October 24, 1910, for semiautomatic telephone exchange systems (Case 200); Serial No. 511,983, tiled August 9, 1 for telephone exchange systems (Case 1 ln the drawings, which comprise ten sheets, Figures 1 to 10 when placed together form a single diagram illustrating the circuits and apparatus involved in an automatic exchange system forming the 'preferred forni of my invention; the lines which extend te the edge of each sheet being continued on the neighboring sheet. 'Tinev roicer arrangement of the sheets for viewme the s stern as a whole is made bv placing Figs. 1, 7,18, 9 and 10 side oy side in order named; by placing lig. 6 above and Fig. 2 below 1; by placing Fig. 3 to the left of 2; and by placing Fig. lshove and below Fig. 3.

lhe'sarne reference numerals indicate the same parts wherever they are shown.

SeZect0rs.-i part of the apparatus involving the preferred form of my invention nml as shown in the drawings herein cornprises automatic selectors or mechanical switchinv devices such as are shown on Figs. 1,?8 and 9.

In the form of automatic switch shown in Fig. 9, which is known as a final selector, the switch carriage or movable element is lprovided with a number of sets of multiple brushes, any particular set of which may be selected for service and the switch carriage is then advanced over a series of sets of line terminals until the selected brushes are brought into engagement with the terminals of a desired line The switch carriage or brush carrying member is of the rotary type, the frame 21 of which is mounted upon a central standard or shaft 22. At the outer end of the frame a number of sets of contact brushes 23, 24, 25 are pivotally mounted upon but insulated from a rod 26, and from each other, in position to sweep over sets of line terminals 27, 28, 29. The brushes have inwardly extending arms 30, bearing against which, one for each brush, are springs 31. Latches 32 one for each set of three brushes, are pivotally mounted upon a rod 36 and arranged to normally hold the brushes from being rocked outwardly into line with the stationary terminals. Bearing against the inner ends of the latches are springs 34 which hold the latches firmly against a stop rod 33. This stop rod 33 serves to prevent the latches from being moved forward too far after the brushes have been released. A stop bar 35 serves to limit the outward movement of the brushes when the latches are withdrawn. The latches 32 and stop bar 35 are of insulating material so that the circuits connected with the brushes will `not be crossed thereby. The springs 31 make electrical connection with the brushes; they areof sheet metal and form the teeth of combs which connect corresponding brushes in the several sets in multiple. Suitable wire clip terminals 37, 38 and 39 are provided for the circuit connections to the springs and brushes.

As the brush carriage lis rotated to cause the brushes to sweep over the fixed terminals, the latchesirst pass by a tripping device or brush selector, by which any desired set of brushes may be released and caused to swing outwardly. This tripping device comprises a shaft 40 provided with radially extending fingers 41 arranged spirally about the `surface of the shaft. This shaft is adapted by mechanism, to be presently de scribed, to be rotated so as to bring the iingers one after another into the line of travel ofthe several latches on the brush carriage. Only one set of brushes is intended to be released in a given operation. 'The shaft is first rotatedto bring a particular linger into position to engage the latch in the samelevel therewith and then f the brush carriage is rotated. ln passing, the outward edge of this latch strikes the end of the flnger, allowing one set of three brushes to be released. Continued movement of the brush carriage brings the selected set of brushes into engagement with the rows of stationary terminals in the same level therewith, these brushes trailing over the terminals and making contact therewith in passing. The brush carriage is finally caused to stop with the selected brushes in contact with some one set of stationary terminals. The other brushes, not being released, are held out of contact with the terminals over which they pass. A further movement of the brush carriage in the same direction of rotationy will carry the brushes over a restoring roller 69, which may be pivoted to the frame and which engages the free ends of the released set, causing them to be pushed back into their normal latched position. After making a full revolution, the brush carriage 1s brought to rest in its normal position again.

The brush selector and the brush carriage of this switch mechanism are arranged to be moved one following the other by suitable motor mechanisms which will impart to each a continuous movement. .in order that the successive positions taken by each movable member may be stepped ed or measured, each is provided with an interruptor device adapted to make and break a contact in the controlling circuit as the moving member passes the several positions at which it may be desired to cause said member to stop. This interrupter device for the brush carriage comprises a pair of contact springs 48, 49 secured to 'the yShaft 22, but insulated from said shaft and from each other. The outer ends of these springs are engaged by inwardly extending arms 44 and 45 of a .pair of levers 42, 43, which are pivotally mounted upon the rod 26. These levers 42 and 43 are insulated from the springs 48 and 49 by small insulating buttons at the ends of the arms 44 and 45, but are uninsulated from the rod 26 which is connected to ground through the frame of the seiector mechanism. In the movement of the brush carriage a roller 51 on the free end of the lever 42 engages the teeth 53 of a cam plate 50, the roller engaging each tooth as the brushes are traversing the space between the successive terminals and dropping into the notches between the teeth as the brushes are centrally located in contact with. said terminals. While the rolle-r 5l is riding over the teeth of the plate 50 the curved end of the lever 43 is in engagement with the' smooth edge 52 of that plate..l relative movement of the levers 42 and 43 is thus obtained by their engagement with the edges of plate 50 and thismovement is, therefore, independent of slight variations in the radial distance between the plate and the axis of movement of the brush carriage. By this construction the duration of contact between the interrupter springs 48 and 49 is made uniform inthe movement of the brush carriage, each make and each break corresponding to a particular position of the brushes with respect to the terminals.

In the normal position of the switch mechanism, the levers 42 and 43 rest in a recess 47 of a normal stop plate 46. The entering edge of this 'plate is covered with insulating material in order to prevent the free ends of the levers 42 and 43 from making electrical contact with the` plate 46 before reaching the full normal position in which the ends of the levers drop into the recess 47.

The interrupter for the brush selector comprises an arm 56 pivoted to the frame at 57, engaging at its free end, a toothed wheel or cam 58 which rotates with the shaft 40. This arm 56 is adapted on the rotation of the shaft 4to engage two contacts 59 and 60. These contacts may be i springs, the free' ends only of1J which are shown in the drawing. Tn its normal position the free end of the arm 56 lies in a notch of the cam 58 which is deep enough to insure an open connection with contact 59.

ii/hen the shaftis away from its normal position, however, connection is made continuo'uslyy with contact 59. The connection with contact 60 is intermittent, this Contact being made when the arm 56 is lifted by each tooth of the cam. There are as many teeth on the cam as there are ugers 4l on the spindle 40 and therefore as many as there are sets of brushes.

The motor mechanism for causing rotation of the brush carriage comprises an annular iron friction disk 61lexibly mounted at the lower end of the spindle 22, an electromagnet62 which may be xed inV any suitable manner to the frame, and a constantly rotating shaft 63 carrying an iron driving '7. roller 64. The disk 6l, roller 64 and that part of the shaft 63 which extends through Y. the center of the electromagnet 62 form the magnetic circuit of the electromagnet 62. 1When therefore current is passed through the winding of the magnet, the roller 64 at- ,.f tracts the disk 6l and causes the latter to Y rotate by frictional contact therewith. holding electromagnet 65 having a pole piece 66 extending upwardly beneath the disk 6l is adapted when current is passed through its winding to engage the disk and hold it from movement. K l, 63 is extended as shown in the drawing vto carry a flexibly mounted driving disk 70, which is adapted to enga-ge a roller 67 carl l ricd by the spindle 40. An electromagnet 66 The power shaft controls the engagement of disk 70 and roller 67 in the same manner vthat the elec- A tromagnet 62 controls the engagement of disk 61. and roller 64. These devices are in fact4 electromagnetic clutches, one to cause movement of the brush carriage and the other to cause movement of the brush selector.

The complete selector switch mechanism is not shown in theA drawing, but the elements-thereof appear in their proper relation to one another sol as to make clear the manner in which the'mechanism operates to interconnect lines. There maybe as `many sets of brushes and stationary terminals as desired. F or example, the switch mechanism may, as a whole, have ten sets of three brushes each and two hundred sets of fixed terminals arranged in ten levels of twenty sets each. .For simplicity in the'diagram there are shown only two sets-of brushes, the 8th and 9th counting from the top down, and six sets of stationary terminals in two levels corresponding to the two sets of brushes shown.

The structure of the automatic selectors or mechanical switching devices shown in Figs. l, 7 and 8 is precisely similar to the structure shown in Fig. 9 and hereinbefore described, with the exception of the interrupter apparatus shown at the top of such structures, the structure and operation of which are as follows: Tn the normal position of thebrush carriage, as shown in Fig. l for example, a pair of levers 42, 43 pivoted upon the rod 26, the latter being insulated therefrom, engage at their free ends a normal stop plate 46. At the end ofv lever 42 is a roller 7l which lies in a recess of yplate 46, and at the end of lever 43 is a right'angle extension arm 72 which makes electrical contact/with said plate 46. A coil spring 54, acting upon an inwardly extending arm 44,

serves to press the roller 7l. with considerable force against plate 46 and thereby holds the brush carriage securely in its normal position. A flat spring 52 engages an inwardly extending arm 45 of the lever 43 and serves to press this lever outwardly but with less force than that of the coil spring 54. The spring 52 also makes electrical contact with lever 43: it is secured to but. insulated from the shaft 22 of the brush carriage and terminates in a wire clip.

As thebrush carriage is moved to carry the brushes over the stationary terminals, the roller 7l and the extension arm 72 en gages the teeth of a cam plate 50. The roller 71 rides over the teeth while the brushes are passing between terminals and drops into a notch as' any released set of brushes is centrall;7 located in direct contact with a set of terminals. The extension arm 'i2 follows behind the roller` one tooth or notch and likewise engages a tooth as the brushes are passing between successive terminals. lt passes through the space between teeth, however, without touching the plate 50, as the released set of brushes is centrally located in contact with the terminals. The stop bar 35 engages the inwardly extending arm 45 just as it does the arms 30 of the brushes and thus prevents the extension arm 72 of the lever 43 from touching the bottom of the notches between the teeth of plate 50, but permitting said arm 72 to touch and make contact with the top of the teeth. The teeth and notches of plate are so spaced and arranged with respect to the contact lever 43 that the extension arm 72 will not break contact with a tooth of plate 50 until after the brushes make contact with the stationary terminals and the roller 71 is ready to drop into a notch. The circuit arrangement, as will presently appear, is such that the motive power for driving the brush carriage cannot be cut olf until the contact is thus broken between lever 43 and plate 50 andtherefore not until the brushes are in position to make good contact with the sta` tionary terminals.

eegucncel switches- The local controlling circuits associated with the 'various parts of the exchange system disclosed herein, which local controlling circuits must be established in denite order at successive stages of the operation of such system to bring into service the different devices or parts as they are required, are in the present embodiment of my invention established by automatic electromechanical switching appliances which are termed se,- quence switches. its will be noted by reference to the drawing, there is a sequence switch associated with the operators connecting circuit and the district selector switch, on Fig. 1 of the drawings; a sequence switch associated with the operators listening-in apparatus on Fig. 6 of the drawings; a sequence switch associated with the cord finder apparatus on lfig. 2 of the drawings; a sequence switch associated with the sender apparatus on lig. 3 of the drawings; a sequence switch associated with the oiiice selector switch on Fig. 7 of the drawings; a sequence switch associated with the group selector switch on lfig. 8 of the drawings; and finally a sequence switch associated with the inal selector switch on Fig. 9 ofthe drawings. Each of these sequence switches consists in its elements of a movable switch operating member, a number of circuit changers or contact devices adapted to be actuated in sequence as said member is moved Jfrom one position to another, an electromagnet, and a motor mechanism operated and controlled by said magnet for advancing said movablemember through its successive positions.

lThe sequence switch may control any de sired sequence of operations whether of the same or of' different devices. ln each position to which this movable member is advanced, ak circuitis established whereby a given operation of the device or devices under control is made possible, and at the same time another circuit is established whereby the motor mechanism of the sequence switch may be actuated automatically when such operation of the deviceror devices under control has been completed: so that as each operation takes place the sequence switch will be automatically moved to the next position, in which position a new operation oranother stage of the same operation will be brought about and so on. Finally the sequence switch establishes a condition whereby the apparatus under control is returned to its normal condition, and also establishes a circuit whereby the sequence switch will be returned to its normal position. ln eachl such position of the sequence switch, the apparatus and its associated sequence switch may be and are preferably so related that local reciprocal controlling circuits will be progressively established by said devices in their operation in such a manner that when a normal operation of either is started, both devices will be progressively carried through a complete cycle of operationswhich may be controlled and checked at different .stages through the agency of energizing circuits established by some other portion ot' the apparatus for this purpose, but which unless so checked will terminate in the automatic return of both the sequence switch and its associated apparatus to normal condition. ln case of a failure of current in such checkingor controlling circuit, even if such failure occurs immediately after a sequence switch and its associated apparatus have started in operation, such sequence'switch and apparatus cannot become permanently displaced or stalled in an onormal condition, but will complete their cycle of operations and be positively returned to normal under control of circuits which are purely local. 4 ln the circuit diagram herein illustrating my invention, the switch springs of the sequence switches are not shown in their actual arrangement with relation to each other or to the movable or commutating member, but are so located upon the drawings as to give the clearest arrangement of circuits. Furthermore, the operating cams are not shown.' rlhe positions of the rotary element or commutating member of each sequence switch in which any of its contacts are closed, are indicated by numbers placed adjacent to such contacts, each contact, except the special Contact which will be hereinafter referred to, being open in all positions except those indicated by the adjacent members. lt may be here noted that all of the sequence switch contacts shown on Fig. l of the drawings form a part of the sequence switch indicated diagrammatically thereon at 101; -that on Fig. 2 all of the sequence switch contacts, the hundreds digit of whose reference character is 2, form-apart of the sequence switch shown thereon at 222, with the exception of the sequence switch contacts 275 and 224; that on Fig. 2 all of the sequence switch contacts, the hundreds digit ot whose lreference character is 3, and also thesequence switch contacts, the hundreds vdigit of whose reference character is 3 von Fig. 5, form 'a part of the sequence switch shown on F ig. 2 at 336; that all of the sequence switch contacts shown on Fig. 6 form part of the sequence switch shown thereon at 176; that all of the sequence switch contacts shown on Fig. 7 form a part of the sequence switch shown thereon at 801; that all of the sequence switch contacts shown on Fig. 8 form a part of the sequence switch shown thereon at 851; and that all of the sequence switch contacts shown on Fig. 9 form a part of the sequence switch shown thereon at 901.

Each sequence switch has, however, as has been before noted, a special contact, governing the local circuit of its motor magnet. These special contacts, which are shown immediately adjacent to the diagrammatic showing of the sequence switch motor magnet, as, for example,'will appear on Fig. 1, the special contact being contact 102 associated with the sequence switch 101, are closed only while the rotary element of the sequence switch is in transit from one stopping position tothe next. For this reason the numbers indicating its condition are placed on the side of the switch lever opposite from the contact and indicate the positions in which such contact is open, such contact being closed at all times while the rotary element or commutating member is in transit between the positions indicated by such numbers. The numbers adjacent to these special contacts of the variousl sequence switches indicate therefore the only positions in which their associated Sequence switches are arranged to stop.

Since, however, sequence switches ot" the character indicated are lwell known in the art, the particular structure and arrangement of the Aform used and shown in the preferred embodiment of my invention need not be particularly described herein and any form thereon which may he suitabie or convenient may be used. t

(rd ndern-The cord iinder tori/ning part of the embodiment oi "my invention herein shown may be of any suitabie construction and arrangement, but preferably involves a set of brushes adapted to sweep over the terminals leading to the various connecting circuits and to stop with its brushes in contact with the terminals leading to the connectingcircnit over which is desired to interconnect a desired line with corresponding magnets operator,

the calling line. The structure of this cord nder may be of any suitable design and the particular structure -forms no essential part of my invention. The mechanism shown, however, comprises five brushes 23D, 232, 233 and 234 and as many sets of live stationary terminals, such as 235, 236, 237, 238 and 239 as there are connecting circuits in an operators position. The brushes are mounted on a carriage adapted to rotate upon a shaft at the lower end of which is flexibly mounted the usual friction driving disk similar to that shown in the `selector switches herein before described. This mechanism also includes the motor mechanism comprising the constantly rotating power shaft, the power magnet and the holding magnet, all adapted to cooperate with the flexibly mounted disk to drive the same and the brushes associated therewith until connection is made with the terminals of the cord circuit taken-for use and then to hold them in such position precisely as do the power and holding apparatus of the selector switches hereinbefore described. rlhe mode of control of the brush carriage of this cord finder is substantially the same `as that of the selector brush carriage and a test relay 229 controls the circuit of said magnets in a manner similar to the modeofcontrol of the of :the selector switch. The operation of the cord finder will sufficiently ap ear from the description of the operation otP my invention as a whole.

ey/s and regsters.-The various circuits which determine the selection controlling operations of the operators sender or controlling equipment shown herein are established by a plurality of recording devices, herein termed registers, which take their positions in response to the operation of manually operable keys controlled by an upon which the designation of the line desired may be indicated. In systems of the character in which my invention is designed to be used some of the lines and trunks, or the lines and trunks at some of the exchanges, may be grouped or classified upon a non-decimal basis and in order to control the proper selection ci line-or trunk where such line or trunk is grouped or classified upon a non-decimal basis, i translation is required in order the number keys, which are usually arranged according to the decimal system, may cause operations of the bodiment shown ing relays,

a set of so-called 6countto control the selection according to the non-decimal grouping of lines and trunks in an exchange.k in the equipment shown, where such translation is necessary or desirable, it is accomplished by the registers referred to, which are in this instance adapted to take positions in resender proper, in the enr spouse to the depression of keys representing a number according to the decimal system, and in such position to control selecting operations according to a non-decimal system, such selection controlling operations governing a selection according to such translated system of the number designated by the keys. lVhen', however, the line 'desired is to be found in an exchange in which the grouping of lines and trunks is upon the decimal system the registers will take positions in response to the depression of the keys representing the number according to the decimal system, and will in turn produce selection controlling operations according to the decimal system of notation. As will be hereinafter pointed out, whether this control will involve translation or not will depend upon the oiice key depressed and will not require any additional or further act by the operator than the depression of the keys indicating the designation of the line desired. I

The registers which are associated with the counting relays also serve to record or store up designations indicated by any combination of depressed keys, and thereby establish permanent conditions for governmg the conditions of selection controlling operations required to cause the selection of the desired line, so that when the call is thus registered or stored up upon one sender apparatus the set of keys may be used thereafter to register another call upon another sender apparatus before the first sender apparatus has finished the selection controlling operations of the first call. There may be, and is preferably,one key for each o lfice or exchange of the system,and also a bank of number keys, which, as diagrammatically indicated, comprise four rows `of tenA keys each, representing the ligures 0 to 9, inclusive, of thousands, hundreds, tens and units digits respectively. These keys, both the office and number keys, are Adesigned to be held in their depressed position by the f locking magnets 422 indicated uponk the drawing, the locking magnet associated with any one set of keys being adapted to retain in its depressed osition the depressedkey of said set o keys until such locking ma et is denergized. Upon the denergization of the locking magnet as sociated with any set of keys the depressed key will be restored to its normal position by means not shown, but which are usual in a paratus of this character. Each key willen depressed vis adapted-to close certain contacts governing circuits which are shown in the diagram and whichl will be hereinafter traced in detail;

The preferred form of the registers, such. v

. group are individual to the corresponding as are used in connection with my invention vpositions of the register `to determine the relays, which relays in turn govern the sethe same as that ofthe sequence switches 6;. hereinbefore referred to and described, with the4 addition of a stop relay. These registers are shown eachas embodying the 4usual power magnet, a stop relay and a plurality of sets of contact devices. The sets of c011- 7c tact devices shown above the power magnet and. stop relay are those connected to the operators keysa'nd by which .is determined the position in which the register will step, and the sets of contact devices located'beiow the power magnet and stop relay upon T" 3 and 5 are the ones closed in the var operation of the sender proper. The registers, as do the sequence' switches, involve a special contact which in the registers is open in each of the positions of the register but closed between each two positions thereof. This special contact is shown imnrdiately tothe left of the associated power .fznzgnet As in the ordinary sequence switches, the contact devices of the registers are open in all the positions except those indicated upon the drawings immedlately adjacent the contact devices. lt will be noted, however, that the positions of the registers range from zero to nine and that there is no normal position of the register, the register remaining, after it has performed its function, in the position in which it was set, and when next taken for use in connection with the operators keys, it starts from such position.

As shown in the circuit diagram, each sender device proper forming a part of my invention may-have, and preferably docs have, six registers associated therewith, corresponding respectively to the districts of the system, the oic'e in a district, and the thousands, the hundreds, the tens and the units of the 'designation of the line desired.

As will be hereinafter described, when the registers are brought successively into association with the sender or selection conltrolling apparatus proper, herein shown as counting relays, the contact devices shown `will ground-conductor 725 leading to the counting relays to control the action of such lectioncontrolling operation of the sender as a whole. It will be noted that both the distri'ctl and office registers respond to the depression of a single key of the set of oflice 125 keys,A whereas the other registers of the sets off keys. It will, therefore, be apparent directly to of the various selector switches which are taken for use 1n the course selves struction. The arrangement and operation that the district and oce registers will respond to the depression of an oliice key to record the district in which such oice is located and which particular office in such district the office corresponding to the depressed key is. The numerical registers similarly will respond to the'depression of the numerical keys to take up positions correspondingto the depressed keys in their respectively associated set of keys. In each position the cams of the registers will close a certain distinctive combination of switch contacts, whereby the operation of the counting relays may be controlled.

Counting relays-Jn the form of my invention shown herein a part of the sender or selection controlling apparatus comprises f a. set of counting relays which in fact may be called the sender proper. These counting I' relays, which in the particular embodiment f of my invention disclosed herein are arranged i 1n two groups of twenty relays each, serve control the selecting operations of establishing rllhe relays themare of any preferred or suitable conthe desired connection.

oi these counting relays will suciently appear in the description of the operation of the system as a whole.

General description mal operation-Taking up now the operation of the system as a whole, it will be observed rst that the eX- change shown in detail in the drawings herewith is assumed to have a capacity of 500 subscribers lines, which lines are .ar- I ranged in two groups of 200 each upon two groups of final selectors such as shown on 1 Fig. 9, and a third group of but 100 lines upon a third group of such inal selectors. l 'lliese final switches are each designed to accommodate 200 lines as noted and have ten a banks of sets of contact terminals, each bank upon the first two groups of nal selectors referred to comprising of such sets. rlhe numerical arrangement of these sets of terminals will be referred to hereinafter. To reach these final selectors, such as shown on Fig. 9, a calling line is rst connectedwith a district selector such as shown on Fig. 1. This district selector in the embodiment of my invention shown herein will select and lind an idle trunk leading to a particular group out of ten groups of oce selectors. When connection has been made by this districtselector between the calling line and an idle oiice selector, the oiiice selector will in turn Vselect and make connection with an idle trunk line leading to the particular olice desired; that is to say, the ofiice in hich the particular desired line terminates. The calling line having been connected by the oiiice selector with the trunk maarre line leading to the desired oce and to the group selector in which this trunk line terminat/es, this group selector now selects and makes connection with an idle inal selector of the particular group in which the line de sired appears.

It will be obvious that, by a proper arrangement and vconstruction of' selector switches, exchanges embodyingmyinvention may be of any desired capacity and such exchanges of various size are within the contemplation` of my invention, the eX- change of the particular size shown being used as an example for convenience and clearness in demonstrating the various features of my invention.

Assuming that the. subscriber whose line and substation apparatus .is shown in the eXtreme left of Fig. 1 desires connection with some other subscriber of the system, for example, No. 854 of the exchange shown in detail herein, which exchange is exchange No. 4 of the system, he will first remove his receiver from its hook 92, thereby closing in the usual manner a circuit for his .line relay 82, causing the lighting of the line lamp 83. 'lhe operator upon receiving this signal will insert the plug 141 of an idle connect ing circuit into the j ack 81 individual to the subscribers line. i4, circuit will now be established from the middle point of the battery 99 through the cord relay 142, sleeve contact of the plug 141, sleeve contact-ot the jack 81, cutorelay 84 of the subscribers line ,to ground and back to battery. The closure oflthis circuit causes the energization of the cord relay 142 and the cutoff relay 84, the cutoit' relay opening the normal connection from the subscribers line to ground and to battery' and causing the denergization of the line relay 82 and the consequent extinguishmentof the line lamp 83, as is usual and well understood.

The insertion of the plug 141 in the jack of tte calling subscriber has also energized the supervisory relay 145 over a circuit which also serves as the talking battery supply circuit of the calling subscriber. rlhis circuit may be traced from the battery 100 through the upper portion of the left winding of the repeating coil 154, listening sequence switch contact 180, tip contact of the plug 141, tip spring of the jack 81, out over one side of the calling subscribers line, through his transmitter, the switch hook 92, primary winding of his induction coil, back over the other side of his line through the ring spring of the jack 81, ring contact of the plug 141,supervisory relay 145, listening sequence switch contact 181, .lower winding of the left winding of the repeating coil 154 and back to battery. The energization of the supervisory relay 145 at this time is to prevent the lighting oi the supervisory signal 156 when the district sequence switch comes into its third position except under control of the calling subscriber, for purposesv which will be hereinafter described.

Upon the attraction of the armature 144 of the cord relay 142 a circuit was established from batteryv through-the listening sequence switch 176, 'listening sequence switch contact 178, front Contact and armature 144 of the cord relay 142 to ground and back to battery. This energizes the listening sequence switch 176 and it moves from its first position, in this movement opening the sequence switch` contact 178 and also the sequence switch contact 179. r1`he listening sequence switch will now move under control of its special contact 177 into its fifth position. 0n coming into its second position, it closed and will maintain closed in its fifth position a circuit from battery through the district sequence switch 101, district sequence switch contact 103, listening sequence switch contact 183, front contact and arm..- ture 144 of thevcordrelay 142`to ground and back to battery. lllhis causes the energization. of the district sequence switch which moves into its second position.

Before investigating what occurs in the district selector apparatus as a result of this movement of the district sequence switch, it will be observed that when tlie listening sequence switch left its fourth position, it opened the sequence switch contacts 180 and 181, closing, however, before these contacts were opened, the cooperating contacts 184 and 185 and also maintaining these contacts closed in its fifth position. llt will be furthermore observed that on coming into the fourth position, it closed the sequence switch contacts 186 and 187 and on coming into the fifth position it closed the sequence switch contacts 188, 189 and 190. ln the fifth position consequently the operators telephone set indicated at 192 will be bridged across the talking strands of the cord circuit and in conversational connection with the calling subscriber, such circuit being traced from the operators set 192 through the normal contact of the upper spring of the key 193, sequence switch contact 184, tip strand of the cord circuit, tip contact of the plug 141, tip spring of the subscriber-s jack 81 and out over one side of his line tothe substation, back over the other side of the` line through the ring spring of the jack 81, ring contact of the plug 141, ring strand of the cord circuit including the supervisory relay 145, sequence switch contact'185, normal contact of the lower spring of the key 193 and back to the operators telephone set. now learn from the calling subscriber the designation of the desired line.

ln the meanwhile, however, the movement tion of the test relay 229 through the se- The operator will of the district sequence switch into its second position has closed a circuit from battery (see Fig. 2) through the cord finder sequence switch 222 of the first idle cord finder, which for the present it will be assumed is the first cord finder associated with this operators position, through the sequence switch contact 202, through the sequence switch contact 27 5 of thesequence switch 272 of the second cord finder of this operators position, common conductor 111, district sequence switch contact 108, back contact and armature 147 of the restoring relay 146 to `ground and back to battery. The establishment of this circuit energizes the cord finder sequence switch 222 which moves into its second position. It will also be observed that the district sequence switch on coming into its second position has closed various other sequence switch contacts for purposes which will hereinafter appear.

Ilhe cord finder sequence switch on coming into its second position has established a circuit for the power magnet 226 from battery through such power magnet, sequence switch contact 205, back contact and armature 228 of the test relay 229 to ground and back to battery. rlhe closure of this circuit energizes the power magnet 226 and the brush carriage 227 begins to rotate. lVhen the brushes 230, 231, 232, 233 and 234 come in contact with the terminals 235, 236, 237, 238, 239 individual to the cord circuit which has been taken for use, a circuit is established from battery through the test relay 229, sequence switch contact 203, brush 230 of the cord finder, contact terminal conductor 112, district sequence switch contact 109, back contact and armature 147 of the restoring relay 146 to ground and back to battery. rlhe closure of this circuit causes the energization of the test relay 229 which, by the attraction of its armature 228 opens the circuit for the power magnet 226, and at the same time closes the circuit lof the holding magnet 242 through the sequence switch contact 207 and the front contact of the armature 228, so that the brush carriage will be stopped and held with. the brushes carried thereby in proper contact with the contact terminals of the cord circuit taken for use.

.-1 circuit is also closed by the energizequence switch contact 217 for driving the cord inder sequence switch 222 out of its second position, and this sequence switch thereupon moves under control of the special contact 201 into its fifth position. 11s the cord finder sequence switch comes into its fourth position, it closes andmaintains closed in its fifth position a circuit from battery through the test relay 229, sequence switch contact 204, reset relay 332, sender sequence switch contact 304, conductor 245,

` enamore brush 232 upon the ,cord'ndencontaQtterminal 237, conductor 115districtasequenoe switch contact. 110, back contact and armature 147 of the restoring relayle to ground and back tobattery.` rThe closure 'of this cir.- cuit providesanew :energizing path for the test relay 229 andenergizes the reset relay The energization of the reset relay 332 has caused it to attract its armatures 333 and 33e, the armature 333 providing for the reset relay332a substitute energizing path around the-; sequence switch contact 304 which Awill befopened as soon as the sender sequence switchmoves out of its irst position,-which ,movement takes place at this time due tothe closure of a circuit for said sender'sequenceswitch 336 through the front Contact. and amature 334 of the reset relay 332and the `sender sequence switch contact 302. 1 Thecircuit now established for the ltest-relay 229 and the reset relay 332 will be --maiutained and these relays kept energized fronrthis timeon so 'long as the cord finder andthe-sender 'are required in connection with the establishment of the desired connection. As will be hereinafter pointed out, thedenergization of these 'two relays at this time. or any time hereafter Awill cause the immediate return of vthe entire cord finder and sender apparatus to their-normal position.

The apparatus which .we have so far considered is now in condition for the depression bythe operator of the various keys shown on Fig. 4 indicating' the designation of the desired line, the district sequence switch being in its second position, the listening sequence switch in its fifth position, lthe cord finder sequence switch in its fifth position and the sender sequence switch in its second position. It will be noted furthermore that the movement `-of the "cord finder and sender sequence switches has taken place rapidlyiand 'while the operator has been-learning from the subscriber the designation of the desiredline. After the operator has once been informed bythe subscriber with what line connection is desired, the listening switch may be moved out of its liftli and into its eighth position to cut out the operators telephone set Without in any way aifecting the operations taking place in the other apparatus shown. This arrangement makes it possible for the operator having learned the designation of the desired line and having depressed the keys corresponding to suc'h designation-to go on with her work without waiting for the various selection controlling' operations to take place. Therefore when the plug of a sec-- ond cord is placed in the jack of a calling subscriber, the movement of its listening sequence switch from its first to its Fifth position, as has been hereinbefore' described in connection with the sequence switch 176,

Iwill close its `sequence switch contact 195 corresponding to the sequence switch contact 182 of the listening sequence switch 176, thereby placing a ground upon the common conductor and closing an energizing circuit for the first listening sequence switch 176 through the sequence switch contact 190. This causes the listening sequence switch 1.76 to move out of its fifth position and cont1nue moving under the influence of its special contact 177 into its eighth position. his movement of the listening sequence switch 176 has entirely disconnected the operators telephone set 192 from the first cord clrcuit by opening the sequence switch contacts 184, 185, 186 and 187. This same movement of the listening sequence switch has completed again the talking strands of the cord circuit by closing the sequence switch contacts 180 and 181. The listening sequence switch 176 will now stayin its eighth position until by the removal of the plug 141 from the jack 81 upon disconnection a circuit is completed for the listening sequence switch through the sequence switch contact 191. and the back contact and arma.- ture 144 of the cord relay 142, or until some tune prior to disconnection the operator desires to again place herself in conversatlonal connection with the calling or called party, at which time she will depress her listening-in` key 197, thereby closing an energizing circuit for the listening sequence switch through the sequence switch contact 175. It will be observed that upon disconnection the circuit for moving the listening sequence switch out of its eighth position will move it intoits first position and it will there come to rest, the sequence switch contact 191 being open iuthe first position of the listening sequence switch and no groundv connection now being completed over the sequence switch contact 178. When, however, prior' to disconnection the operatordepresses -her listening-in key 197, the listening sequence switch will not stop inrits irst position, but will continue to move into its fifth position when the operators telephoneset 192 will be again bridged across the talking strands of the associated cord circuit. `This movement is accomplished by the circuit through the sequence switch contact 175L and the listening-'in key 197 which drivesv the listening sequence switch from ,its eighth into its first position and by the circuit including the sequence switch contact 178 and thef front contact and armature lli-tof the cord relay 142 which drives the listening sequence switch from its first position, it moving/into its fifth position underthe influence of its special contact 17 7.

The listening-in key 197 it should be noted is individual to the cord circuit with which it is associated, but the master wipe out key 199, vthe master listeningout 'key 198 and the master flash back key 196, the function of which keys will vbe hereinafter described, are common to an operators position and are associated with a particular cord only when the listening sequence switch of such cord is in the listening or fifth position. 1t may also be noted that so long as the key 193 remains in its normal position, the continuity .of the talking strands of the cord circuit is maintained in all positions of the listening sequence switch either' directly through the sequence switch contacts 180, 181, or through the contacts of the key 193. At all vtimestherefore, while the plug 141 is in the -jack 8l of the calling subscriber, he will be supplied with talking current from the 'battery 100 through the talking strands of the-cord circuit and the tip and ring contacts of the plug 141. i

'The operator having learned that the calling subscriber desires connection with a particular line, in this linstance as assumed line No. 354 of exchange No. 4 of the system,` and the various sequence switches having come into the positions hereinbefore noted awaiting the depression of the keys. it now only remains for the operator to depress the keys according to the line designation as sumed in order to produce the necessary selection controlling operations. `It may here be noted that the operations ofthe district cord finder and sender sequence switches have been brief and rapid, and in practice such operations will be complete before the operator has learned the line designation from the calling party. At this point, therefore, the operator depresses the fifth or No. 4 oiiicekey 436 (see Fig. 4), the first or No. 0 thousands key 433, the fourth or No. 3 hundreds key 434, the sixth or No. 5 tens, key 427, and the fifth or No. 4 units key 435. Before considering the results of theI depression of these keys, it will be observed that the cord finder `sequence switch upon coming into its second position, closed and now maintains closed thesequence switch contacts 208,209 and 210. The closure of the sequence switch contact 210 has established a circuit for the x respective'holding magnets 422 of the various sets of keys, such circuit being traced from battery through the holding magnets 422 in parallel, conductor 244, sequence switch contact 210 to ground and back to battery. 'When, therefore, the keys 'above referred to were depressed,'they were held in their depressed position by the various holding magnets 422 and will be maintained held in their depressed position until such time that they are no longer needed in connection with this particular call and maly be used in connection with lsome other cal reaches what may be called its fifth or No.

4 position, in whichposition the ,Contact device 509 thereon will be closed, as is indicated upon the drawings by the ligure 4 adjacent thereto. At this time a circuit will be established from battery through the conductors 502 and 510, district Aregister stop relay 511, contact device 509, left contacts of the office 4key 436 to which said contact device is connected to ground and back to battery. The district'register stop relay 511 will therefore be immediately energized, attracting its armature and thereby opening the energizing circuit of the district regis'- .ter power magnet, causing the register to stop in its fifth or No. 4 position. The same movement of the armature 505 has closed a circuit from battery through the sonder sequence switch 336, sequence switch contact.

511, conductor 246, sequence switch contact 208, conductor 423, right contacts of the depressed ofce key 436 to ground and back to battery. The closure of this circuit causes the sender lsequence' switch 336 to move out of its second position into its third position, in which movement the energizing circuit just traced is open at the sequence switch contact 306. 1n the position to which the district register' has been moved and has now stopped, but a single contact device thereon other than the contact device 509 before referred to is closed, and this contact device is indicated at 617 (see Fig. 5).

The depression of the ofiice key436 has also caused the energization of the office reg.l

ister power magnet 504, such power magnet being connected by the armature 506 and its back contact of the office register stop relay 517 in parallel with the district register power magnet ini the circuit heretofore traced. Thel office register thereupon begins to move and continues its movement until the contact device 515 is closed in the iifth or No. 4 position of the office register, at which time a circuit is closed for the oilice register stop relay 517 through the contact device 515 and the left contacts of the de'- pressed oiiice key. 'l his causes the energiza.- tion of the oilice register stop relay, which thereupon 'attracts its armature 506. opening los 

